Drafting instrument



April 19, 1927. 1,625,735

M.MAURER I DRAFT I NG I NSTRUMENT Filed Nov. 2l, 1925 Patented Apr. 19, I927.

raza'ztt MICHAEL MAURER, 0F SPISSKA NOVA VOS, GZECI-IOSLOVAKIA.

DRAETING INSTRUMENT.

Application filed November This invention relates particularly to that type of drawing instrument whereby paral lel lines can be drawn, and which comprise two rulers or straight-edges united and movable about a pivot so that they can be set at different angles, and be folded compactly together, there being a suitably disposed arcua-te scale adjacent the pivot whereby that straight-edge which is to be used for guiding the pencil or the like can be set and se cured at any desired angle with relation to the other straight-edge by means of a clamping-screw or other means; other instruments for drawing lines diagonally, having also, been, in some instances, adapted for use in conjuction with a horizontally disposed scale whereby successive movements thereof over a sheet of paper anc, consequently, the dis tance between the lines drawn, can be easily predetermined.

The object of my invention is to provide an instrui'nent which, possessing all the attributes appertaining to other instruments of similar type, will be extremely eflicacious, and durable and capable of being very cheaply manufactured.

With the object, above referred to, in view, the invention consists in the particular construction and combination of parts as hereinafter described and defined in the appended claiming clause.

The subject of the application is shown in the accompanying drawing, wherein:

Figure 1 shows the drawing instrument when in opened position; Fig. 2 illustrates same when closed; Fig. 3 shows the same adjusted for hatching.

The drawing instrument consists of rulers b, a connected together at the articulation point a and movable relative to one another at said point. At the end of the ruler Z) a semi-circular plate (Z provided with a scale division from O to 90 is secured in such manner that the central point of the are which forms the circumference of the plate occurs at the articulation a. The end of the ruler 0 connected with the ruler b is of a concave circular shape so that the concave end of the ruler c fits the arcuate circumference of the plate d. For the purpose of holding the rulers b, 0 together, the plate f provided with cut out portions is used, which is secured on the one hand to the ruler c, and on the other hand is pivotally attached to the ruler b at the articulation point a. If necessary use may also 21, 1925. Serial No. 70,641.

be made, on the backside of the rulers, of such connecting plates. The plate 7' is provided with an indicator 0 showing the degree of adjustment as well as with a nonius scale. On the inner edge of the ruler Z), aplate g is secured which is provided with a guiding groove h of arcuate shape. In said guiding groove, a pin 2' provided with a screw head is introduced which is secured at the free end of the strut j advantageously bent arcuately and rotatably connected with the ruler c, and which, by means of the screw head can be fixed in any position. On the plate 7' or directly on the ruler c is secured the guiding rail is which stands transversely to the edge of the ruler, in which rail the indicator Z provided with a longitudinal slit, is movably introduced transversely to the edge of the ruler 0. For the purpose of fixing the position of the indicator Z, the screw it is used. The auxiliary ruler or T- square m belongs to the drawing instrument, but it is made separately from the same. O11 said auxiliary ruler transverse to the edge, parallel strokes equidistant from one another are made in several rows lying behind one another, so that the parallel strokes are at a different distance from one another in the different rows.

When drawing lines with different inclinations, the rulers Z2, 0 are opened round their point of movement at until the indicator or the plate f shows the desired inclination angle. During the opening the pin 2' is guided in the groove h of the plate g, which owing to the arcuate form of the groove works freely and easily. If the rulers are adjusted to the desired inclination angle, the screw i is tightened by means of a milled head, whereby the two rulers are fixed in the desired inclination to each other.

In the case of hatching, the auxiliary ruler m is fixed as required on to another ruler, for instance, a set ruler 39 (Fig. 3), preferably in such manner that the edges of both rulers are parallel to each other. The ruler c is then placed on the longitudinal edge of the ruler m, the rulers Z), 0 are then adjusted at the desired inclination angle, they are fixed and the indicator Z is moved in the guiding rail 7c so that the same extends above the auxiliary ruler m. The ruler c is then displaced along the ruler m and a straight line is then drawn each time along the ruler b, as the indicator Z is brought successively into registration with the desired division Mid strokes of the auxiliary ruler. According to the thickness of the hatching the indicator Z is adjusted into alignment with the corresponding row of the different divisions of the auxiliary ruler.

lVhat I claim is A drawing instrument comprising a straight-edge, a protractor member bearing a scale, secured to an edge thereof at one end of said edge, a guide plate having an arcuate slot secured to said straight-edge, a second straight-edge, a plate carried thereby, means pivoting said first-named straight-edge to said plate concentric with said protractor, said plate having an opening through Which the protractor scale may he read, a strut having one end pivoted to said second-named straight-edge, means connecting the other end sliding-1y in said slot, a pointer on the second-named straight-edge, and adjustable normally to said edge and a third straight edge having a scale thereon for co-operation with the said pointer.

MICHAEL EVIAUHER. 

